chapter 9-12 review - CHAPTER 9 MUSCLES AND MUSCLE TISSUE...

This preview shows page 1 - 12 out of 67 pages.

CHAPTER # 9 MUSCLES AND MUSCLE TISSUE
Figure 9.1 Bone Perimysium Endomysium (between individual muscle fibers) Muscle fiber Fascicle (wrapped by perimysium ) Epimysium Tendon Epimysium Muscle fiber in middle of a fascicle Blood vessel Perimysium Endomysium Fascicle (a) (b)
Figure 9.2c, d I band I band A band Sarcomere H zone Thin (actin) filament Thick (myosin) filament Z disc Z disc M line (c) Small part of one myofibril enlarged to show the myofilaments responsible for the banding pattern. Each sarcomere extends from one Z disc to the next. Z disc Z disc M line Sarcomere Thin (actin) filament Thick (myosin) filament Elastic (titin) filaments (d) Enlargement of one sarcomere (sectioned lengthwise). Notice the myosin heads on the thick filaments.
Ultrastructure of Thick Filament Composed of the protein myosin Myosin tails contain: 2 interwoven, heavy polypeptide chains Myosin heads contain: 2 smaller, light polypeptide chains that act as cross bridges during contraction Binding sites for actin of thin filaments Binding sites for ATP ATPase enzymes
Ultrastructure of Thin Filament Twisted double strand of fibrous protein F actin F actin consists of G (globular) actin subunits G actin bears active sites for myosin head attachment during contraction Tropomyosin and troponin: regulatory proteins bound to actin
Figure 9.8 Nucleus Action potential (AP) Myelinated axon of motor neuron Axon terminal of neuromuscular junction Sarcolemma of the muscle fiber Ca 2+ Ca 2+ Axon terminal of motor neuron Synaptic vesicle containing ACh Mitochondrion Synaptic cleft Junctional folds of sarcolemma Fusing synaptic vesicles ACh Sarcoplasm of muscle fiber Postsynaptic membrane ion channel opens; ions pass. Na + K + Ach Na + K + Degraded ACh Acetyl- cholinesterase Postsynaptic membrane ion channel closed; ions cannot pass. 1 Action potential arrives at axon terminal of motor neuron. 2 Voltage-gated Ca 2+ channels open and Ca 2+ enters the axon terminal. 3 Ca 2+ entry causes some synaptic vesicles to release their contents (acetylcholine) by exocytosis. 4 Acetylcholine, a neurotransmitter, diffuses across the synaptic cleft and binds to receptors in the sarcolemma. 5 ACh binding opens ion channels that allow simultaneous passage of Na + into the muscle fiber and K + out of the muscle fiber. 6 ACh effects are terminated by its enzymatic breakdown in the synaptic cleft by acetylcholinesterase.
Figure 9.9 Na + Na + Open Na + Channel Closed Na + Channel Closed K + Channel Open K + Channel Action potential + + + + + + + + + + + + Axon terminal Synaptic cleft ACh ACh Sarcoplasm of muscle fiber K + 2 Generation and propagation of the action potential (AP) 3 Repolarization 1 Local depolarization: generation of the end plate potential on the sarcolemma K + K + Na + K + Na + Acetylcholine
Figure 9.18a
Figure 9.18b
Figure 9.19a Coupled reaction of creatine phosphate (CP) and ADP Energy source: CP (a) Direct phosphorylation Oxygen use: None Products: 1 ATP per CP, creatine Duration of energy provision: 15 seconds Creatine kinase ADP CP Creatine ATP
Figure 9.19b Energy source:

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture